06 Beam Instrumentation, Controls, Feedback, and Operational Aspects
T17 Alignment and Survey
Paper Title Page
WEPAF066 The New CLIC Main Linac Installation and Alignment Strategy 1979
  • H. Mainaud Durand, J. Gayde, J. Jaros, M. Sosin, A. P. Zemanek
    CERN, Geneva, Switzerland
  • V. Rude
    ESGT-CNAM, Le Mans, France
  A complete solution has been proposed for the pre-alignment of the CLIC main linac in 2012 for the Conceptual Design Report. Two recent studies provide new perspectives for such a pre-alignment. First in a study on Particle Accelerator Components' Metrology and Alignment to the Nanometre scale (PACMAN), new solutions to fiducialise and align different types of components within a micrometric accuracy on the same support were proposed and validated, using a stretched wire. Secondly, a 5 degree of freedom adjustment platform with plug-in motors showed a very accurate and efficient way to adjust remotely components. By combining the results of both studies, two scenarios of installation and alignment for the CLIC main linac are proposed, providing micrometric and automatized solutions of micrometric assembly, fiducialisation and alignment in metrological labs or in the tunnel. In this paper, the outcome of the two studies are presented; the two scenarios of installation and alignment are then detailed and discussed.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPAF066  
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WEPAF067 Alignment and Monitoring Systems for Accelerators and Experiments Based on BCAM - First Results and Benefits of Systems Developed for ATLAS, LHCb and HIE-ISOLDE 1983
  • J. Gayde, B. Di Girolamo, Y. Kadi, G. Kautzmann, F. Klumb, R. Lindner, D. Mergelkuhl, L. Pontecorvo, M. Raymond, P. Sainvitu, E. Thomas
    CERN, Geneva, Switzerland
  • F. Blanc, P. Stefko
    EPFL, Lausanne, Switzerland
  In the last few years alignment and monitoring systems based on BCAM* cameras active sensors, or their HBCAM evolution, have been developed at the request of the Technical Coordination of LHC experiments and HIE-ISOLDE facility Project Leader. ADEPO (ATLAS DEtector POsition) has been designed to speed up the precise closure - 0.3 mm - of large detector parts representing in total ~2500 tons. For LHCb a system has been studied and installed to monitor the positions of the Inner Tracker stations during the LHCb dipole magnet cycles. The MATHILDE (Monitoring and Alignment Tracking for HIE-ISOLDE) system has been developed to fulfil the alignment and monitoring needs for components of the LINAC enclosed in successive Cryo-Modules. These systems have been in each case configured and adapted to the objectives and environmental conditions: low space for integration; presence of magnetic fields; exposure to non-standard environmental conditions such as high vacuum and cryogenic temperatures. After a short description of the different systems and of the environmental constraints, this paper summarizes their first results, performances and their added value.
* BCAM: Brandeis CCD Angle Monitor, http://alignment.hep.brandeis.edu/Devices/BCAM/
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPAF067  
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WEPAF068 Frequency Scanning Interferometry as New Solution for on-Line Monitoring Inside a Cryostat for the HL-LHC project 1986
  • H. Mainaud Durand, T. Dijoud, J. Gayde, F. Micolon, M. Sosin
    CERN, Geneva, Switzerland
  • M. Duquenne, V. Rude
    ESGT-CNAM, Le Mans, France
  Funding: Research supported by the HL-LHC project
For the HL-LHC project, the cryostats of the key components will be equipped permanently with an on-line position monitoring system based on Frequency Scanning Interferometry (FSI). Such a system, based on absolute distance measurement, will determine the position of the inner triplet cold masses w.r.t. their cryostat and the position of the crab cavities also inside their cryostat, within an uncertainty of measurement of 0.1 mm, in a harsh environment: cold temperature of 2 K and high radiation level of the order of 1 MGy. The FSI system was validated first successfully on one LHC dipole cryostat and its associated cold mass to undergo qualification tests under different conditions: warm, vacuum and cold (2K). The FSI system also equips the first crab cavities prototype cryostat. The configuration of the FIS system chosen after simulations, the conditions of tests as well as their results and analysis are presented in this paper.
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPAF068  
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WEPAF069 Evaluation of Frequency Scanning Interferometer Performances for Surveying, Alignment and Monitoring of Physics Instrumentation 1990
  • J. Gayde, S.W. Kamugasa
    CERN, Geneva, Switzerland
  During the last three years, the performance of Frequency Scanning Interferometry, accurate to a few micrometres, has been evaluated at CERN in the frame of the PACMAN project. Improvements have been studied and tested to make it better suited for typical alignment and survey conditions in accelerators and experiments. The results of these developments and tests, coupled with the multi-channel capability of the system, and its compactness which eases its integration in the area to be surveyed, offer a wide scope of possible applications for in-situ large scale metrology for physics equipment and facility elements. Furthermore, the fact that the system electronics can be placed far away from the position to be measured, allows the system to be used in confined and hazardous spaces. This paper briefly describes the system and its improvements. It gives the precision obtained for distance measurements and for the 3D point reconstruction based on FSI observations in the case of CLIC component fiducialisation.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPAF069  
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WEPAL070 HLS System to Measure the Location Changes in Real Time of PAL-XFEL Devices 2345
  • H. J. Choi, J.H. Han, H.-S. Kang, S.H. Kim, H.-G. Lee, S.B. Lee
    PAL, Pohang, Kyungbuk, Republic of Korea
  All components of PAL-XFEL (Pohang Accelerator Laboratory's X-ray free-electron laser) were completely installed in December 2015, and Hard X-ray 0.1nm lasing achieved through its beam commissioning test and machine study on March 16, 2017. The beam line users has been performing various tests including pump-probe X-ray scattering, time-resolved x-ray liquidography, etc in the hard x-ray beam line since March 22. The energy and flux of x-ray photon beam generated from XFEL and synchronization timing should be stable to ensure successful time-resolved tests. Several parts that comprise the large scientific equipment should be installed and operated at precise three-dimensional location coordinates X, Y, and Z through survey and alignment to ensure their optimal performance. As time goes by, however, the ground goes through uplift and subsidence, which consequently changes the coordinates of installed components and leads to alignment errors ΔX, ΔY, and ΔZ. As a result, the system parameters change, and the performance of the large scientific equipment deteriorates accordingly. Measuring the change in locations of systems comprising the large scientific equipment in real time would make it possible to predict alignment errors, locate any region with greater changes, realign components in the region fast, and shorten the time of survey and alignment. For this purpose, a HLS's (hydrostatic leveling sensor) with 0.2um of resolution are installed and operated in a waterpipe of total length 1km in the PAL-XFEL building. This paper is designed to introduce the operating principle of the HLS, the installation and operation of the HLS system, and how to utilize the HLS system in order to ensure beam stabilization.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPAL070  
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The Kilogram Redefined  
  • A. Steele
    NRC Measurement Science and Standards, Ontario, Canada
  It is anticipated that the General Conference on Weights and Measures (CGPM) will, at its 26th meeting 13-16 November 2018, revise the SI that links the definitions of the kilogram, ampere, kelvin, and mole to exact numerical values of the Planck constant h, elementary charge e, Boltzmann constant k, and Avogadro constant NA, respectively, and which revises the way the SI is defined including the wording of the definitions of the SI units for time, length, mass, electric current, thermodynamic temperature, amount of substance, and luminous intensity so that the reference constants on which the SI is based are clearly apparent. Feature article Scientific American 2017 Feb. After a brief historical introduction to the SI, speaker will chart the motivation and conceptual framework for this momentous change, and the technologies being developed for its introduction. This talk would be a few days in advance of World Metrology Day 2018.
Speaker: Dr. Alan Steele / Measurement Science and Standards laboratory in Ottawa, part of Canada's National Research Council (NRC)
slides icon Slides WEEGB1 [7.733 MB]  
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THPML095 Improvement of Wire-Stretching Technique to the RF Measurements of E-Center and Multipole Field for the Dipole Cavities 4885
  • G.-T. Park, J. Guo, H. Wang
    JLab, Newport News, Virginia, USA
  • A. Overstreet
    ODU, Norfolk, Virginia, USA
  • B. P. Xiao, T. Xin
    BNL, Upton, Long Island, New York, USA
  Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
After the first publication* of wire-stretching technique from its principle to measure the electrical center of a deflecting cavity, more refinements of this techniques including the review of its analytical and simulation results, RF circuit improvement to improve the signal to noise ratio and its application to other cavities have been developed. These applications include the electrical center measurements for the LHC RFD and DQW crabbing cavity prototypes, multi-frequency harmonic kicker cavity for JLEIC electron cooler**, TE011 cavity developed for the beam magnetization measurement***, and a separator cavity at BNL****. Further development of measurement calibration, error reduction, alignment of cavity installation to the machine beam line, and multipole field analysis for the beam dynamics will be presented.
*H. Wang, Proceedings of NAPAC2016, pp225-228
**S. A. Overstreet, BS Thesis 2017, Guilford College, Greensboro, NC
***J. Guo et al. these proceedings
****T. Xin et al, these proceedings
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPML095  
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